How to test Wi-Fi near a cordless phone base

Does your Wi-Fi pause or lag when you use a cordless phone, or when you sit near its base? A quick comparison can show whether the connection behaves differently in that spot, but it cannot identify the source of interference on its own.

Use the Wi-Fi Signal tool to watch response time, jitter and lost requests. Test in the same place with the cordless phone idle and during a call, while keeping other conditions as steady as you can.

Test Wi-Fi beside the cordless phone base

1. Open Wi-Fi Signal on the device whose connection you want to check. Keep the device in one spot near the phone base for the whole comparison.
2. With the cordless phone idle, let the live results run for about a minute. Note the usual response time, whether jitter changes a lot, and whether any requests are lost.
3. Make or receive a call, then watch the same results for about a minute. Keep the handset and your Wi-Fi device in their original positions. If the call ends, repeat the comparison once to see whether the change happens again.
4. Repeat the same idle and call checks a few feet farther from the base. If possible, also compare another device connected to the same Wi-Fi network, in the same location.

For a useful comparison, avoid moving the router, starting a large download, or changing Wi-Fi networks between runs. If other people are streaming or gaming, note that too. A busy network can cause changes that have nothing to do with the cordless phone.

What the result means

The results stay similar during the call

If response time, jitter and lost requests look about the same with the phone idle and in use, the call probably is not causing a clear connection change in your test. That does not rule out occasional interference, but it makes the phone a less likely explanation for interruptions you cannot reproduce.

Jitter or lost requests increase during calls

A repeated increase during calls suggests the connection is less steady at that time. It does not prove the cordless phone is responsible. The router, other wireless devices, a crowded Wi-Fi channel, or changes in your internet connection can produce similar results. Repeat the test at another time, and compare from farther away.

The connection is poor whether or not anyone uses the phone

If the results are consistently poor, the cause may be a weak Wi-Fi connection, a busy router, or a problem farther along the internet connection. The browser test measures how the connection behaves, not the Wi-Fi radio signal strength in dBm, and it cannot pinpoint which device or network segment caused a lost request. For a broader way to separate weak Wi-Fi from a slow internet connection, see Is your Wi-Fi weak, or is it the internet?.

Only one device shows a change

If another device stays steady in the same place, the affected device may be using a different Wi-Fi band, have a weaker antenna, or be switching between access points. Check its connection and repeat the comparison before changing router settings.

How to reduce interruptions

1. Move the cordless base away from the router. Try a few feet of separation, and avoid placing either device behind a television, inside a cabinet, or beside other wireless equipment. Repeat the idle and call comparison from the same test spot.
2. Try a different Wi-Fi band. If your router offers 5 GHz or 6 GHz Wi-Fi and your device supports it, connect to that network and repeat the test. These bands do not use the 2.4 GHz Wi-Fi band, though they may have less range through walls. If your router gives the bands separate network names, choose the intended name in Windows 11 under Settings › Network & internet › Wi-Fi, or on a Mac under System Settings › Wi-Fi.
3. Check the cordless phone's band and model. Cordless phone systems do not all use the same radio frequencies. Some older models operate around 2.4 GHz, while many DECT systems use a different band. Check the phone's manual or label rather than assuming every cordless phone shares a frequency with 2.4 GHz Wi-Fi.
4. Change the router's 2.4 GHz channel if needed. Open the router's app or administration page and look for its wireless or Wi-Fi settings. If the router allows channel selection, try a different channel and repeat the same comparison. The exact setting names differ by router, so use its instructions if you cannot find the option.
5. Restart and update the router. Restart it using its normal controls, then check its app or administration page for a firmware update. Afterward, test again under similar conditions so you can tell whether the change helped.
6. Check for wider connection problems. If drops continue in several rooms and on multiple devices, test at a different time and check whether other people are using the network heavily. The phone may be unrelated, and persistent problems may need attention from your internet provider or router support.

Why a cordless phone may affect Wi-Fi

Wi-Fi and cordless phones use radio signals, but their frequency bands vary by device and region. A phone that uses a band near 2.4 GHz Wi-Fi could contribute to interference, especially when the base and router are close together. Other sources of wireless interference or a busy router can create similar symptoms.

Wi-Fi Signal reports connection behavior such as response time, jitter and drops. A change in those results tells you that the connection behaved differently during the test, not that the tool detected a cordless phone or measured radio interference directly. The strongest clue is a repeatable difference between otherwise similar tests, followed by improvement when you increase the distance or switch Wi-Fi bands.